Updating all rows at once in codeigniter, error in query - php

Question

I am trying to update multiple rows simultaneously and I think my query is somewhat messed up while i am trying to update all my rows simultaneously. I am using CodeIgniter framework. I want to work on my query and the data being sent from the view but unable to get a logic to update all rows simultaneously. Please note that there should be only one update button as this is a requirement
My View code is:
<form action="" method="post">
<table border="1" style="background:none;width:100%;" RULES="ROWS" class="tab_data">
<thead>
<th width="30px">No</th>
<th >Action Item</th>
<th>Responsibility</th>
<th>Order</th>
<th>Mandatory?</th>
<th width = "100px" align="center">Actions</th>
</thead>
<tbody>
<?php
$serial_no = 1;
if(count($rows))
{
foreach($rows as $row)
{
?>
<tr>
<td><?php echo $serial_no; ?></td>
<td>
<?php
echo "<input type='hidden' class='col-md-4 form-control' name='checklist_id' value='"
.$row['checklist_id']."' />";
echo $row['action_item'];
?>
</td>
<td>
<?php echo $row['responsibility']; ?>
</td>
<td>
<input type="hidden" name="row_id[]" value="<?php echo $row['sequence']; ?>">
<input type="text" class="form-control" name="order[]" value="<?php echo $row['sequence']; ?>">
</td>
<td>
<input type="checkbox" class="" name="if_checklist<?php echo $row->checklist_id; ?>" value="1" echo 'checked'; >
</td>
<td align="center">
<?php
echo anchor('exits/delete_absconding_checklist/'.$row['checklist_id'],
"<i class='fa fa-trash-o' alt='Delete' title='Delete' rel='".$row['id']."' ></i>",
array('rel' => $row->id, 'class' => 'edit_row'));
?>
</td>
</tr>
<?php
$serial_no++;
}
}
?>
<tr>
<td></td><td></td><td></td><td></td>
<td>
<input type="hidden" name="action" value="update_order">
<button type="submit" name="submit" class="btn btn-info pull-right">Update</button>
</td>
</tr>
</tbody>
</table>
</form>
My Controller Code is:
function display_absconding_checklist()
{
if($this->input->post('action') == '_doDelete' || $this->input->post('action') == '_doChangeStatus')
{
$this->admin_init_elements->delete_rows('applicant_status');
}
if($this->input->post('action') == 'update_order')
{
$this->exit_common->update_absconding_checklist();
}
$data['rows'] = $this->exit_common->get_all_absconding_checklists();
$this->data['maincontent'] = $this->load->view('maincontents/backend_display_absconding_checklist', $data, true);
$this->load->view('layout', $this->data);
}
My Model code is:
function update_absconding_checklist($post_array)
{
$post_array = $this->input->post();
foreach($post_array['checklist_id'] as $key => $rowid)
{
if($rowid > 0)
{
if(isset($post_array['if_checklist'.$rowid]))
$in = '1';
else
$in = '0';
$sql1 = "UPDATE pr_absconding_checklists SET `action_item` = '"
.$post_array['action_item'][$key]
."', `sequence` = '".$post_array['sequence'][$key]
."', `if_checklist` = '".$in
."' WHERE `checklist_id` = ".$rowid;
}
else
{
$sql1 = "UPDATE pr_absconding_checklists SET `action_item` = '"
.$post_array['action_item'][$key]
."', `sequence` = '".$post_array['sequence'][$key]
."', `if_checklist` = '".$in."'";
}
$query1 = $this->db->query($sql1);
}
}
I am getting no errors but there are many errors in my code and i am messed up, i am attaching my table snapshot also, please recommend improvements
My Table name is pr_absconding_checklists